The Man from Volvo

[jfm]

Re: burnt valve=forget hydraulicing

apparently there's an oil jet that sprays lube oil onto the underside of piston, cooling it. If that was bust (as VP allege) it would deny cooling to the piston, hence scorched. I think.

 

[jfm]

Re: Never threaten, just state

Totally agree. Things like this are what make the other side realise you know what you're doing. Many settlements received by fax at 11.45 when you have said you're going to do something horrid at noon, and they know from your past conduct you're not a wolf-crier

 

[Guest]

Re: burnt valve=forget hydraulicing

hydraulicked a diesel powered jeep in deep water once. I can confirm the following:

it smoked like a b*stard ever after
there was sod all power afterwards
taking in enough water to bend a con rod stops the engine dead

I'm sorry, but it is stretching credibility to claim you can hydraulic a diesel and not notice. We nearly went through the windscreen when ours went...

 

[tcm]

Re: more questions

um still not enuf info. The heat rises, burns the valve, then with less pressure there's hydraulicing.

Firstly, not sure if an oil jet in a cylinder is sposed to cool the piston - the piston is designed in ally to withstand high temps, is oval to allow for differential temps around valves, and expands to fill the piston. Oil in the cylinders is there to oil the rings and bores. So egr's explanation sounds iffy. Either way, lets says there was no oil coming out of that hole, so the heat increased, the valve chipped, the rod bent.

Now, how does the engineer reach the hydraulicing issue? Hydraulicing of course begins to deflect the blame elsewhere. If there was a fair load of water in the oil, then praps it did hydraulic.

But if the valve chipped first, then that cylinder would have been open and sucked water in on the inlet or ignition stroke?

My point is that with the piston heating and ex valve burning, then the hydraulic ... it's an engine failure covered by wty?

It's not a nice shiny engine magically bent internally (which it would be if purely hydrauliced with no notice) - and it didn't move an inch after the hydraulicing.

 

[jfm]

Re: Jeep incident

Graham,
see your point, you'd notice big time if the piston was stopped dead by solid water in the cyl. VP are saying Dom did it Yonks ago and didn't realise.....yer right

Separate point, dya know if you hydrauliced via the inlet or the exhaust? I still think exh hydraulicking is incredibly unlikely, whereas inlet is easy in a jeep in deep water (unless one of those big tall intake pipe jobs?)

 

[jfm]

Re: more engineering blathering

Agree. If the valve damage occured first, then water splooshed up the exhaust, it could suck in water on the inlet stroke, when the exh valve is meant to be shut. But then you would get a "soft hydraulic" (a new eng term just invented by jfm, all rights reserved), becuase on the compression stroke the water could piss back out through the very same hole (i mean the poorly seated valve) it came in, so no bent conrod imho? Also it wd need to be a biggish hole in the valve seat becuase you have to fill the cyl displacement at TDC before there's any hydrualicking at all, in other words there's an inherent safety margin

AFAIK oil squirts are used for piston face cooling sometimes. Not because the piston alloy cant take the temp, becuase managing the combustion requires cooler surface I think.

Also I thort the oval shape was to allow for uneven thermal expansion cause by metal around the gudgeon pin (hence ovalness, see what I mean?) not because of localised heat near the valves? Variations, across the face of the piston, in net heat transfer from valve to piston face (radiation only) would be minimal I wd think? Speshully in 4 valve head?

Whichever way you look at it the VP theory sounds bolx. I think either no hydraulicking occured, of if it did it was after the valves failed. Agree your comment that there must, absolootely must, be water in oil if hydraulicked, salt as well because sea water, so that wd be a good thing to test for, and very cheap too. Good place to start - Dom have you kept oil sample?

 

[Deleted User YDKXO]

Re:jurisdiction

I accept that totally in that jurisdiction is vital to the interpretation of the warranty under the contract, all I was saying was that I thought that liability for the warranty would depend on who was party to the contract but you have very eloquently addressed that point in your other reply

 

[Guest]

Re: Jeep incident

It was very definitely through the inlet.

 

[coliholic]

Re:jurisdiction

I have a vague recollection that Dom bought the boat from a Jenneau dealer in France. Is that corrrect Dom? In which case presumably jurisdiction would be France. would that be better or worse from a consumer rights point of view?

Following the thread with fascination. Can't add anything to the undoubtedly excellent engineering and legal skills and expertise (or bullshit) demonstrated by all and sundry, but sounds v. good. Time for Dom to put his hand in his pocket and get some proper paid for legal and professional engineering advice. I would have thought sooner rather than later.